South Australia’s oldest-ever solved cold case disappearance will end without wife-killer Geoffrey Gordon Adams being sentenced for manslaughter.

Adams pleaded guilty to manslaughter but denied he murdered his 24-year-old wife Colleen Adams inside their matrimonial home at Maitland, on the Yorke Peninsula, in November 1973.

Her remains were not found until September 2018 – after Adams confessed to killing her.

The jury acquitted him of murder in August this year and he was awaiting sentencing.

Justice Peek on Monday released a letter from Royal Adelaide Hospital consultant physician Dr Patrick Russell that stated Adams had been diagnosed with glioblastoma multiforme – a “primary brain cancer that carries a grim prognosis”.

“His neurological deficit has taken a steep change for the worse, now completely paralysed on the left, unable to open that eye or move his arm or leg,” Dr Russell said in the letter, dated December 10.

“He is ill and considered medically unstable at this point. He is certainly not fit to stand for sentencing.

“On his current trajectory, I expect him to die within a few weeks, likely in hospital.”

Police dig for Colleen Adams’s remains in 2018. Photo: ABC News: Simon Christie

The Supreme Court was told on Monday that Adams was not expected to survive last weekend, but was still alive.

His case was adjourned until April next year.

‘False narrative’ for decades

For 45 years, Adams told police and the media that his wife walked out on him and his two toddler daughters.

Adams said his wife was “continuously having a go at me over nothing”, in a recorded police interview played to the jury throughout his trial.

During the trial, prosecutor Jim Pearce QC told the jury that Adams spent almost half-a-century “peddling a story” to police and the media.

“It was a version that took 45 years to rear its head,” he said.

“He spent 45 years creating a false narrative of a mentally unstable woman who abandoned her children.”

Colleen Adams’s sisters Kristina Burford and Heather Johncock outside the Supreme Court. Photo: ABC News: Meagan Dillon

Following the verdict, Ms Adams’s sister Heather Johncock said the family found justice after 45 years of not knowing where their loved one was.

But she expressed disappointment that Adams was not convicted of murder.

“I knew she wouldn’t have run away and left her children — I knew she would never, ever do that, it wasn’t in her nature,” she said in August.

“She was a very loving mother; she loved her children and doted on them very much.”

-ABC